Safely handle empty OIDs and other weird cases where we can't find a sub-id.

Fixes https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=7219

svn path=/trunk/; revision=44460

1 files changed, 9 insertions, 0 deletions

diff --git a/epan/oids.c b/epan/oids.c
index e2452560ab..e15717f467 100644
--- a/epan/oids.c
+++ b/epan/oids.c
@@ -938,6 +938,15 @@ guint oid_encoded2subid(const guint8 *oid_bytes, gint oid_len, guint32** subids_
 	*subids_p = subids = ep_alloc(sizeof(guint32)*n);
 	subid_overflow = subids+n;
 
+	/* If n is 1 then we found no bytes in the OID with first bit cleared,
+	 * so initialize our one byte to zero and return. This *seems* to be
+	 * the right thing to do in this situation, and at the very least it
+	 * avoids uninitialized memory errors that would otherwise occur. */
+	if (n == 1) {
+		*subids = 0;
+		return n;
+	}
+
 	for (i=0; i<oid_len; i++){
 		guint8 byte = oid_bytes[i];